Application of Unmanned Aerial Vehicle (UAV) in the assessment of beach volume change – A case study of Malgund beach

Typically, various factors influence natural beaches, including wave and tide forces, wind and river sediments, etc. These are primarily responsible for erosional and depositional processes that occur during extreme weather events such as cyclones or typhoons. As a result, coastal topography is extremely complicated in nature and requires frequent monitoring. Such information is crucial for coastal engineers and scientists to make critical choices on coastal zone management. Conventional data collecting methods, such as the Global Positioning System (GPS), aerial photography, satellite imagery, and airborne light detection and ranging technology (LIDAR), all have drawbacks, including lengthy processing times and relatively expensive costs. Alternative technologies, like the Unmanned Aerial Vehicle (UAV or drone) methodology, have been popular in recent years for mapping and monitoring coastal elevation changes. The study employs a drone to monitor beach sediment changes in Malgund, India, located along the Ratnagiri coast. This beach is placed between two headlands, and images were acquired using a UAV (quadcopter) equipped with a 4k camera over a 6km spatial extent. A high-resolution Digital Elevation Model (DEM) was generated from the collected drone data, and established Ground Control Points (GCP) were utilized to validate the developed model. The validated datasets showed a good correlation coefficient (r=0.86), and cross-sectional profiles were retrieved to identify and quantify coastal erosion. In summary, this study demonstrated the efficacy of UAVs for monitoring short-term changes in beach morphology and sediment budget.